vla-Offset directions

[CarmeloLabadie]

I'm a little confused... I've read in all the vla-Offset posts about the difficulty in determining the direction of the offset. Have things changed for 2007? I get the following consistent results:

LINE: + to left & - to right
ARC: + increase radius & - decrease radius
LWPOLYLINE: + to right & - to left

Obviously this makes things so much easier.

[Emmanuel Delay]

Lines, polylines have a direction. 

You can draw a line from left to right, or from right to left.  

Just like polylines have an order of which point came first ...

 

Depending on that the offset can do the opposite thing, depending on whether the distance is positive or negative.

Test my code (type a number for getdist instead of setting two points) on the dwg I uploaded.

 

 

;; Custom OFFset
(defun c:coff ( / mspace myline dist offLine)
    (vl-load-com)

    (setq mspace (vla-get-modelspace (vla-get-activedocument (vlax-get-acad-object))))

    (setq myline (vlax-ename->vla-object (car (entsel "\nSelect object to offset: " ))))
    (setq dist (getdist "\nOffset Distance : "))
    (setq offLine (vla-Offset myline dist))
    (princ)
    
)
(princ)

 

offset.dwg

Edited November 23, 2021 by Emmanuel Delay

[mhupp]

This might help

http://www.theswamp.org/index.php?topic=57171.0

[BIGAL]

Like mhupp answered some where else.

 

My $0.05 I use pick near end of line pline etc this determines the direction uses a compare end points to pick point.

[dexus]

I have used parts of this code in the past to determine the side:

https://autocadtips1.com/2011/07/04/autolisp-offset-polyline-segments/